Experimenting with attaching the GoPro to the under side end of the boom using the GoPro helmet strap mount. Each strap goes around each arm of the boom and pulled tight on the buckles. Then used the safety strap tethered to the boom to keep all the strap ends out of the way. See how it goes tomorrow.
that's cool. I have cut two slots to insert a belt in the base that comes with the package, that should give extra options. Would be good if others could post their solutions.
Here some footage using the standard GoPro helmet strap setup to mount the GoPro on the end of the boom as in pics on this thread
I think it's worked ok 
